A New Shark and Ray Fauna from the Middle Miocene of Mazan, Vaucluse

Swiss J Palaeontol (2011) 130:241–258 DOI 10.1007/s13358-011-0025-4 A new shark and ray fauna from the Middle Miocene of Mazan, Vaucluse (southern France) and its importance in interpreting the paleoenvironment of marine deposits in the southern Rhodanian Basin Nicolas Vialle • Sylvain Adnet • Henri Cappetta Received: 10 March 2011 / Accepted: 29 August 2011 / Published online: 16 September 2011 Ó Akademie der Naturwissenschaften Schweiz (SCNAT) 2011 Abstract Recent paleontological excavations of the the last decades from several localities in the Natural Park Middle Miocene sandstones (top of the ‘‘Schlier’’ facies) of Lube´ron (South of Vaucluse). Selachian associations near Mazan, Vaucluse (southern France) uncovered a rich recovered in the Middle Miocene of Vaucluse are quite selachian teeth assemblage including 34 shark and ray particular because they indicate either neritic or deepwater species. This great diversity of selachian taxa provides new deposits. Such difference in faunal composition between information about the palaeoenvironmental settings of sites can be interpreted as a difference in age, a geo- some Middle Miocene deposits in the southern Rhodanian graphical heterogeneity of environmental deposits or a basin. For instance, the co-occurrence of some deepwater mixture of both. A new fossil locality, found in 2007 near Squaliformes and Rajidae with numerous Carcharhinifor- Mazan, was collected by one of the authors (H. Cappetta) mes and Myliobatiformes, usually inhabiting the conti- with the kind help of Eric Collier. A preliminary analysis nental shelf, suggests a deepwater deposit inshore, as indicates that the new rich selachian fauna comprises both adjacent to a submarine canyon area. types of the previous associations. The aim of this work is to improve our knowledge about the selachian diversity in Keywords Selachians Á Middle Miocene Á Southern the southern Rhodanian basin during the Middle Miocene, France Á Southern Rhodanian basin Á Paleoenvironment by listing in detail the selachians from Mazan and com- paring them with material collected in Vaucluse and in neighbouring areas of He´rault. Introduction The earliest studies on the Miocene fossil selachians from Geological settings Vaucluse were by Fischer (1878); Leriche (1906) and Joleaud (1907, 1912) who published a detailed review of The fossil locality of ‘‘Mazan’’ (Fig. 1) is located at the selachian remains from the southern Rhodanian basin. eight kilometres east of Carpentras (GPS coordinates: These faunas were partially updated from new material N044°03002.800 E005°08015.800) and is mapped as ‘‘Helve- (Cappetta et al. 1967; Ledoux 1972) or from comparative tian’’ (BRGM 1975) formally equivalent to the Langhian– analysis with nearby contemporaneous localities (Cappetta Serravallian period. This age was formerly reported as 1970, 1973). More recently, Brisswalter (2009) published a Vindobonian by Demarcq (1970), a local stage which note on new selachian teeth assemblages collected during corresponds precisely to the lower part of the so-called ‘‘Helvetian’’, and thus, to the Langhian only. The sediment consists of grey sandstone, composed of sorted sand, that N. Vialle Á S. Adnet (&) Á H. Cappetta outcrops as a monotonous layer around Carpentras (Joleaud Laboratoire de Paleóntologie, UMR 5554, Institut des Sciences 1907, 1912). The thickness of this layer varies between 350 de l’Evolution, Universite´ de Montpellier II, Sciences et and 500 m (Demarcq 1970) according to its erosion and Techniques du Languedoc, Cc 064, Place Euge`ne Bataillon, 34095 Montpellier Cedex 5, France location. This unnamed formation probably corresponds to e-mail: [email protected] the upper part of the blue ‘‘Schlier’’marls Formation that 242 N. Vialle et al. Fig. 1 Left. Map of the major Miocene deposits of Vaucluse with Lithostratigraphic framework of the Rhone–Provence Molassic series, selachian teeth: 1,‘‘Bonpas’’; 2, ‘‘Caumont’’; 3, ‘‘Mazan’’; 4, ‘‘Saint- simplified from Besson et al., 2005. Black: continental surfaces, grey: Didier’’; 5, ‘‘Cabrie`res d’Aigues’’ (redraw after Demarcq, 1970 Bioclastic limestone-dominated deposits (‘‘molasse’’ s.s.), white: modified and Besson et al. 2005 for the Latest Burdigalian network of Sand and marl-dominated deposits. Fl.In: Major Fluvial incisions fluvial valleys: L. Burd fluvial valleys). Right. Early-Middle Miocene occurs in the entire ‘‘Miocene Molasse basin in the Rhone– dried, then treated with a 10% solution of acetic acid over Provence’’ area (Gignoux 1960; Demarcq 1970). Besson a period of 1 or 2 days according to the size and quantity et al. (2005) recently confirmed the Langhian age of these of the residues. After rinsing in clean water and drying, peculiar sandstones and sandy marls, which are sand- the final residues were sorted under a binocular micro- wiched between two major molasse deposits (see Fig. 1). scope. The fossil material consisted exclusively of iso- In these sandstones layers, Joleaud (1907, 1912) and lated selachian teeth, many teeth and vertebral centra of later Cappetta et al. (1967) reported a relatively deepwater Actinopterigians and fragmentary bones of marine ver- shark fauna near ‘‘Bonpas’’, at the SW of our study area. tebrates. The selachian teeth, particularly those of sharks, Closer, the fossil locality of ‘‘Saint-Didier’’ (Ledoux 1972) were often in poor state of preservation with only the exhibits similar sandstone layers and a similar selachian crowns remaining. The smaller teeth, ranging in size fauna with numerous deepwater taxa. These deepwater between 2 and 4 mm were the most complete. The poor faunas are clearly different from those previously recov- preservation of the larger fractions is probably due to ered elsewhere in the Middle Miocene of southern Rho- taphonomic bias. This assumption is supported by danian basin by senior authors (Fischer 1878; Leriche observation that many small teeth are rounded, suggesting 1906; (Joleaud 1907, 1912) but they are consistent with that the material may have been carried on the sea floor recent studies (Besson 2005; Besson et al. 2005) on the before final deposition. It is thus possible that part of dynamics of the ‘‘Rhodano–Provençal’’ basin that observed material collected at ‘‘Mazan’’ was not strictly autoch- that the Middle Miocene has been marked by two maximal tonous and has been transported from nearby. All the transgressions, one dated as Langhian and the second as figured material is housed in the University of Montpellier Serravallian. (Collection number with abbreviation MAZ). The sys- tematics and dental terminology of taxa follow Cappetta (1987, 2006). The studied fossil material represents 25 Systematic palaeontology species of sharks belonging to 22 genera and 9 species of rays shared in 8 genera. Only three genera are recognized A 60 kg sediment sample was sieved through a series of as exclusively fossils: Paraheptranchias, ‘‘Oligodalatias’’ screens, the finest of which was 0.3 mm. Residues were and Carcharoides. A new shark and ray fauna from the Middle Miocene of Mazan, Vaucluse (southern France) 243 Order Hexanchiformes Buen, 1926 well marked like the distolingual depression. A well- Family Heptranchidae Barnard, 1925 developed uvula with small mesial foramina is present on Genus Paraheptranchias Pfeil, 1981 the lingual face (Fig. 2-1b). The infundibulum opens Paraheptranchias repens (Probst, 1879) beneath the uvula, at the level of the well-developed Notidanus repens (Probst, 1879) transverse lingual bulge, and is followed by a more or less Notidanus avenionensis (Joleaud, 1912) marked groove toward the basal edge of the root. The Material: 5 incomplete teeth. upper tooth has a narrower and more erect cusp than the lower teeth. The distal heel is well separated from the main This unusual species is represented by incomplete frag- cusp. The apron is broader at its base. On each side, there ments, primarily of the crown, probably those of lower are two small foramina. On the lingual face there is a small teeth. The root is missing. The main cusp is highly uvula, which is not well marked. Beneath the uvula, there developed with a sigmoid shape. The mesial cutting edge is are two axial foramina followed by a slight groove. limited to the upper part of the cusp. The cusp is flanked by Remarks. The presence of a slightly serrated mesial small denticles, which generally separate the acrone from cutting edge and absence of fold on the uvula are indicative the accessory cusplets. of the living species Centrophorus granulosus. This species Remarks. This peculiar species was described by Probst is widespread in the Miocene sediments of Vaucluse, from (1879) in the early Miocene of Germany and well illus- the Early to Late Miocene (Cappetta et al. 1967; Ledoux trated by Barthelt et al. (1991). Joleaud (1912) also 1972; Cappetta 1975; Brisswalter 2009). reported a unique specimen of P. repens, formerly as Notidanus avenionensis, from the Middle Miocene deposits Genus Deania Jordan & Snyder, 1902 in the region of Avignon, southern France (Cappetta 1970, Deania aff. calceus (Lowe, 1839) 1987). Material: 10 teeth. (Fig. 2-2, 2-3) Family Hexanchidae Gray, 1851 Compared to Centrophorus, lower teeth of Deania are Genus Hexanchus Rafinesque, 1810 more compressed labiolingually and the crown is narrower. Hexanchus sp. There is no serration on the mesial cutting edge. On the Material: 2 teeth. labial face (Fig 2-2a), the apron is very wide and thick, but its limits are slightly marked from the root. On each side of The two teeth are both crown fragments, probably from the apron, there are two well-developed marginal foramina. lower teeth. The crown is easily separated from the pre- The labial depression is well marked. On the lingual face vious taxon by the large number of accessory cones, which (Fig. 2-2b), the uvula is well marked but small and is decrease regularly distally. On one tooth, one can observe a flanked by marginal foramina, which reappear beneath the small serration on the lower half of the mesial cutting edge straight bulge and may be followed by a slightly marked of acrocone.

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